Vehicle brake system



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Filed Sept. 9. 1943 March l5, 1949.

Filed sept. 9. 1943 H. C. MACK VEHICLE BRAKE SYSTEM 5 Sheets-Shea?I 3 gli.,

IN VEN TOR. c'. MA cw,

March 15, 1949. H. c. MACK 2,464,327

VEHI CLE BRAKE SYSTEM Filed Sept. 9. 1943 5 Sheets-Sheet 4 :PIII-alf] f4' INVENTOR. HARLEY GMAC/f,

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March l5, 1949. H, c, MACK 2,464,327

vEHIcLE BRAKE SYSTEM Filed spt. 9, 1945 5 sheets-sheet 5 Patented Mar. 15, 1Q49 UNITED STATES PATENT OFFICE VEHICLE BRAKE SYSTEM Harley C. Mack, St. Louis, Mo. Application September 9, 1943, Serial No. 501,690 1o claims. (ci. 19a-f3) This invention relates to a power and brake control for motor vehicles and the like, and it consists in the constructions, arrangements and combinations herein described and claimed.

It is a particular object of the invention to provide a novel construction of pedal in which the forward acceleration and braking action is accomplished by a single foot pedal.

It is a further object of the invention to provide a braking system in which the brakes are automatically applied upon removal of the foot from the accelerator pedal, or in which the pressure upon the pedal is reduced, thus lending the braking system of unusual value in case the operatorof the vehicle should become permanently or temporarily incompetent of controlling the vehicle.

More particularly, it is the object of the invention to provide a novel braking system in which a vacuumcreated by the engine of the vehicle will function in the application of the brakes.

Itis a still further object of the invention to provide a novel braking system in which the accelerator pedal controls the power of the engine as well as the brakes, thus adapting the system to holding of a vehicle upon an up-grade. without necessity of separate brake application or riding" of the clutch as is often practiced, in order to hold the vehicle against backward rolling.

It i-s also an important object of the invention to provide a power and brake control in which a decided saving of gas is important and in which wear on the brake lining and the vehicle is reduced to a minimum.

Additional objects, advantages and features of invention will be apparent from the following description considered in conjunction with the accompanying drawings, wherein Figure 1 is a fragmentary sectional view of a conventional vehicle (including a brake pedal) having my brake system installed, in braking y Figure 7 is a front elevation of the manual control valve.

Figure 8 is a section on the line 8-8 of Figure 7.

Figurev 9 is a cross section on the line l-i of Figure 8.

Figure 10 is a side elevation of a modified form of control valve.

Figure 1l is a horizontal section therethrough.

Figure 12 is a vertical section on the line I2l2 of Figure 11.

Figure 13 is a vertical section on the line l3-i3 of Figure 11.

Figure 14 is a side elevation of the control valve removed from the valve housing.

Figure 15 is an enlarged sectional detail of the throttle control.

Figure 16 is a fragmentary sectional-.view illustrating a braking system in which con .rol of the valve is eiected by the use of braking uid of a hydraulic brake system, the parts be g shown in braking position.

There is illustrated formally an engin III of conventional construction including as usual an intake manifold H and a carbureter I2. t e engine being suitably supported upon the chassis I3 of the vehicle, as is customary. A conventional iloor Il and dash-board II is shown for support o1' mechanism presently to be described.

As shown in Figure 1. there is a foot brake It forming a part of the present day motor vehicle, operatively connected to a master cylinderll whereby application of the brakes of a vehicle may be effected. The connection between the master cylinder I1 and respective brake is not shown, since such construction is well understood and it is believed not essential to the understanding of my braking system. I alsov show a conventional accelerator I8 and foot pedal I9 for feeding gaseous fuel to the engine, connections between the accelerator and the carburetor also being omitted, since the arrangement may vary in different types of motors. It is suiiicient to say that when the accelerator is depressed, the throttle of the carburetor is opened so as to increase the speed of the engine. The accelerator is not directly depressed by the foot of the operator but is actuated by means of a novel foot control pedal 20.

The control pedal is formed from suitable gauge sheet metal having a forward foot portion 2l and a heel portion 22. The heel portion 22 is formed with a forward recess 23 at a level below the rearmost portion 24. By this construction, the pedal will be readily adapted to men and women drivers. Intermediate the foot portion 2l' and the heel portion 22, an arch support 25 is suitably mounted, preferably formed of rubber or other suitable material, preventing slippage as well as a comfortable support for the foot, and the foot anA heel portions are also rubber-coated.

'I'he pedal 20 includes a depending leg 25 within which there is keyed or otherwise rigidly secured a shaft 21. the latter being rockably supported between a pair of brackets 28 fixed upon the floor board I4 (see Figure 6). As may be seen in Figure 2, the pedal 20 is mounted so as to extend in a longitudinal plane directly above the accelerator or -foot pedal viii and is movable in a downward direction so as to engage and depress the accelerator I8.

The pedal 20 is operatively associated with my braking system, and as may be seen from a consideration of Figure 1, the shaft 21 has fixed thereto a downwardly extended lever 29 of sub-` stantial length. adjacent the lower end of which a brake rod 30 is pivotally connected by means of a clevis 3 i.

A power cylinder 32 is mounted upon the chassis I3 by means of a bracket 33, the cylinder 32 being disposed in advance of the lever 28 a suitable distance. 'I'he cylinder 32 is of the diaphragm type, as may be seen from Figure 5. The cylinder 32 is more or less conventional in construction and consists of a pair of hollow casing members suitably iianged for securing a diaphragm 34. the latter having suilicient clearance to flex from one casing member into the other, for a purpose to be explained. Upon the rear of the diaphragm 34 a rod 35 is suitably secured as at 35, being pivotally connected to the lever 29 above the point of connection of the rod 30. Upon the opposite or front side of the diaphragm 34 a helical spring 31 is mounted, one end of the Spring engaging a suitable seat on the diaphragm with the other seat upon the forward casing member 32'. Thus the spring functions to hold the diaphragm in a neutral medial position. The casing member 32' is axially bored to receive a fitting 38 of a hose line 39 which is operably connected with a manual control valve 40, asy will be explained hereinafter.

Attention is now invited particularly to Figure 4 for an understanding of the construction of a control valve, generally indicated by the reference character 4I, the structural details of which have been specifically described in my United States Patent No. 2,197,664. The valve consists of a casing 42 having a centrally disposed chamber 43, the rear end of which is closed by a screw-threaded plug 44 into which a rod 45 is threadedly engaged, as at 45, the rod terminating in a clevis 45'. The casing 42 is extended forwardly to provide a cylindrical extension 41 of the chamber 43, which normally, when the brake is oi. abuts against a collar 48 connected with the brake rod 30. This position is indicated in dotted lines in Figures 3 and 4. The valve casing 42. at diametrically opposite sides is provided with a pair oi ports 45 and 50. 'I'he vacuum port 48 leads directly into the interior of the cylinder 43 and its outer end opens into a threaded bore forming a connection with a flexible vacuum line 52 which in turn is connected with the intake manifold Il of the engine, the connection of which will be described hereinafter. vThe suction port 50 is in communication with a threaded port 53, establishing a connection with a flexible hose 54, the other end of which is connected with the rear end of a power cylinder 55, as indicated at 55. 'I'he power cylinder 55 is of conventional construction and is mounted upon the chassis by a bracket 55. A brake rod 51 is operatively connected to the piston of the power cylinder 55, extending forwardly for connection with a brake lever 58, the latter being connected with the piston rod 58 of the master cylinder I1.

A storage tank 50 is suitably mounted upon the chassis, preferably having a capacity of 1000 cubic inches. and as may be seen in Figure 2, the hose line 52 is connected to a fitting 5| in communication with the Vtank 50 upon the opposite side of the fitting 5l, a check valve 5I' being suitably installed in the line 52.

With further reference to the control valve 4I, shown in detail in Figure 4, a reciprocable piston valve 52 is disposed within the chamber 43, having a head 53. The head is hollow and communicates with a, hollow stem 54, which projects through the extension 41, the latter being formed with a neck 41', which closely surrounds the stem 54. The hollow head and the bore of the stem constitute a reservoir for lubricant. 'I'he bore is closed at the head end of the piston valve by means of a threaded plug 55. The head of the valve is provided with a lubricating port 51 and with grooves 58. The stem is formed with an annular flange 69 which ilts within the extension 41 of the valve casing and this flange is provided with an annular groove 10. Surrounding the stem and disposed within the extension 41 there is a compression spring 1I which bears at one end against the flange 69 and at its other ends against the end wall of the extension 41 and kforces the valve to its closed position. The terminal of the stem 54 is engaged with a threaded end of the brake rod 30 and is pinned thereto at 12. The bore 55 is provided with an opening 13 which discharges oil against the inner face of the extension 41'. The bore or chamber 55 is designed to contain a special heavy lubricant such as a, mixture of graphite and grease for the purpose of keeping the piston valve and the stem 40 lubricated at all times.

The valve casing is formed with a chamber constituting an air duct, the wall of which is designated 14, the chamber being lled with a filter material 15. 'I'he end of the chamber is open but extended thereacross is a wire netting 15 holding the lter material in place. An arcuate groove 11 is formed between the flange 52 and the head of the valve and this arcuate groove in closed position of the valve communicates with the chamber 14 and with the entrance of the valve casing on the outlet side thereof. When the valve is in open position as shown, the suction of the engine will draw air across the valve chamber throughA the port 50` and hose line 54 for application of the brakes through the power cylinder 55. In the closed position of the valve, however, there will be no communication through the port 50, but communication will be established between the brake actuating mechanism and the chamber 14 so that air may enter to break the vacuum in the power cylinder 55.

From the foregoing it will be seen that I have provided a, piston valve for application of the brakes of a, vehicle by employing the suction created by the engine. However, should the engine go dead, manual application of the brakes is still possible as will be apparent from the following construction- The stem 54 includes a shoulder 18 complemental to a shoulder 19 formed upon the interior of the chamber 43. Thus, a forward pull on the brake rod 30 by backward pressure on the control pedal 20, will cause a forward movement of the control valve 4| with a similar movement of the rod 45. A lever 50 is associated with the clevis 45', pivoted to a iixed 5 fulcrum 8|, as at 82. The pivot 82 is located only a short distance below the clevis 45' and the lower end of the lever 8| is operatively connected to the brake rod 51 as at 83. This pivoting of the lever 80 increases the movement o1' the lower end oi' the lever for a purpose, as will appear. Thus, the rod 51 will be moved rearwardly imparting movement to the brake lever 58 with consequent operation oi the vmaster cylinder |1 for applying the brakes.

It will be understood that the vacuum hose lines 52 and 54 have sutlicient slack to permit longitudinal movements of the valve 4| and it will be seen that the lever 80 and the brake lever 29 bear the main support of the valve 4|. However, if desired, any suitable slip hanger supports (not shown)may be employed for additional support of the valve, although such an arrangement has not been found necessary.

The connection of the suction hase lines 39 and 52 with the manual control valve 40 and the intake manifold will now be explained. The valve 40 is suitably mounted upon the dash l5 of the vehicle, and as shown in Figure 9 consists of a tting having diametrically opposed threaded ports 85 and 86, each opening upon a medial circular chamber 81. The bore 85 receives the hose line 39 therein-which leads from the miniature power cylinder 32, while the bore 86 receives va hose line 88 operatively connected to a branch 89 of a T-tting 90. A plug valve 9| is rotatably mounted in the chamber 81 and includes three passages 92, 93 and 94 of progressively decreasing diameters, the passages extending entirely through the plug body and are so arranged as to be selectively aligned between the bores 85 and 86 for free passage of suction therethrough. The plug 9| is rotated by means of an indicator handle 95 conveniently located upon the dash 84. The handle 95 includes a pointer 96 complemental to indications 91 on a face plate 98. We will say that the handle is moved to the indication 1" which will have brought the passage 94 into registry with bores 88 and 81, to establish a vacuous condition in the valve, the rate being determined by the size of the bores in the valve 9|. If however, the valve is rotated so that the pointer registers with the indication 2," then passage 93 is brought into registry with the bores 85 and 88 and since this passage is of greater diameter, a higher vacuous condition is involved, and if the nal passage 92 is brought into registry with bores 85 and 96, a complete vacuous condition is involved by reason of the increased diameter of the passage. If the indicator is moved to the ofi position, then suction is closed off entirely, and the brakes would thus have to lbe operated manually, by slight downward heel pressure on the control valve pedal 20.

The suction hose line 52 includes a check valve 99 operable to admit suction into the line 52 through branch line 52 connected to a branch of the T-fitting 90. A branch |0| ofthe T-tting forms a connection for a suction line |02, the other end of which is connected to the intake manifold of, the engine. The nal branch |03 of the T-iitting 90 has a suction line |04 connected to a piston cylinder |05.

The cylinder |05 is employed for effecting full closure of the throttle valve |06 which is essential where hydromatic shifting of the transmission gears is involved. The cylinder |05 consists of a head |06' having an axial nipple for connection of the hose line |04, the opposite end being closed with the exception of an axial bore s 4 |01 through which a piston rod |08 of a piston |09 is extended. A tension spring ||0 is interposedibetween the piston |09 and the closed end of the cylinder tending to hold the valve |08 closed. The spring ||0 allords suillcient pull to maintain the valve |08 closed sumciently for manual gear shifting, but where hydromatic shifting is involved a fully closed throttle valve must be inherent, and this is'assured by suction through the line |04. As soon as the throttle valve |08 is opened, the vacuum inthe cylinder |05 is partially broken, allowing normal acceleration oi' the motor. Any suitable connection between the piston and throttle valve may be employed, but in the present case, the rod |08 is pivotally connected to onearm ||0' of a bell crank lever, which is pivoted on the engine head or otherwise. The arm of the bell crank lever connects to a link ||2, which in turn is. pivotally connected to the shaft of the throttle valve |08.

The structure of the brake illustrated in Figure 3 is identical to that shown in Figures 1 and 2, with the exception that the foot brake lever |8 is omitted. This construction would be followed in new car construction. The same reference characters have been employed to designate corresponding parts.

In Figures 10 to 14, I have illustrated a modiiied construction of foot control valve in which a tandem piston provides a control, highly efcient where high pressure air or vacuum is employed in applying the brakes. Attention is particularlyinvited to Figure 11, wherein a cylindrical casing 4| is shown, the chamber 43' of which is closed by a threaded plug 44' having a rod 45 threadedly engaged axially thereof. The casing includes a suction port 50' with which a vacuum line 54' is associated. A port 5| is provided in the casing, communicating with the chamber 43 and has a vacuum line 52' which is operatively connected to the storage tank 80, as in the rst case. An air duct or chamber 14 is also employed which in addition tothe screened opening, additional openings ||8 are provided upon the underside of the chamber. It will be noted that the ports 50' and 5| are not in direct alignment as in the rst instance, but are offset or spaced longitudinally apart which is essential by employment of the particular type of piston valve. The casing 4| has a forward concentric hollow reduced extension 4 axially bored for reciprocation of a piston rod 84' which is connected to the brake rod as previously explained.

A tandem piston ||5 is reciprocably mounted with the chamber 43 and consists of a front and rear piston elements ||6 and ||1 respectively, integrally formed upon a reduced body member I8. The rear end of the body member is formed with reduced projecting boss 9 transversely slotted as at |20 for reception of a screwdriver for holding the piston against rotation when making the connection with the brake rod 80 or for adjusting the position of the piston within the chamber, as will be presently explained. The body of the piston 8 is formed with a forward reduced extension |2| forming a shoulder |22. The extension |2| is further reduced in diameter to dene a piston rod 64' which is projected through an axial bore in the extension ||4 for connection with the brake rod 30. A shoulder |23 is thus formed at the juncture of the piston rod and the extension |2|. A compression spring |24 encircles the extension |2| and the rod 64' one end of which abuts the shoulder |22 and ascesa?- 'I the other bears upon the inner end wall |25 of the extension III. The spring holds the piston in its closed position, as shown in Figure 11.

In order that a snug pressure-tight ilt may be had between the walls ofy the chamber 43,'l and the piston elements ||3 and ||1, these elements are each formed with anvannular groove |23, of a width and depth to receive a pair of split piston rings |21.

-The operation of the control valve 4|' is the same as in the case of the valve 4|, but it will be noted that in the closed position of the valve as shown in Figure 11, the suction line 52' is continuously open to the chamber 43',.between the piston elements I I3 and ||1,`so that upon forward movement of the piston ||5 a slide control of suction through the ports 53' and 5|' is accomplished.

The operation of my braking system will be readily understood from thefollowing description, it being assumed that the indicator hand 95 has been set so as to align port 34 with ports 85 and 83 (see Figure 9), which would be desirable for driving at high speeds, since the small restricted port has a tendency to reduce acceleration resistance and will not hinder instant automatic brake action, since at high speeds in most motors, when the throttle is closed the motors will develop better than 23 inches of vacuum. Thus a small port is sufficient for proper braking action. For low speeds, such as city driving, the port 33 would be employed. which is larger than the port 94, because at low speeds vacuum is more or 'less reduced through intermittent throttle opening. The port I2 is employed where an emergency, harsh brake action, is required, but is only recommended for city driving or short trips, since driving resistance against acceleration becomes too great and may cause fatigue 'on long trips.

With the motorflii operating a suction is created in the manifold the pipes 52, 33 and |04. The suction pip32 unseats the check valves 39 and 5|' creating a suction in tank 30 and builds up a vacuous pressure therein. The piston 34 of the control valve 4| is at this time open so that suction is created through ports 49 and 50, the pipe line 54 and to the power cylinder 55. The suction in the power cylinder draws upon the rod 51 which in turn rocks the lever 53 forwardly and thereby actuates the master cylinder Il, which applies the brakes. Suction through pipe |04 draws the piston |03 to close the throttle valve |03 and suction through the pipe 33, the valve 43 and the pipe line 39 actuates the diaphragm 34 to draw the rod 35 and the lever 23 in a direction toward the engine, thus moving the pedal 20 to its rearmost position, as shown in Figure 1.A

When it is desired to put the vehicle into motion, the pedal 20 is depressed (as in ordinary acceleration) until -it encounters the foot pedal I9, the latter opening the throttle |06 through the accelerator I3, the suction in cylinder |05 being overcome, free opening of the throttle valve being permitted. `The vacuum in the power cylinder 32 is also counteracted by reason of backward movement of the rod 35 through similar movement of the lever 23. When the lever 23 moves rearwardly the valve 62 is moved correspondingly until the ports 49 and 5|! are closed, shutting of! suction therethrough. When the valve 32 is closed the power chamber 55 is vented through 11 and the chamber 14. In the event that the motor should go dead. the storage tank il will function to provide suction for operation of the brakes.

In the event that the automatic brake feature is to be eliminated and it is desired to have a direct manual brake application, the indicator hand 3.5 is moved to the o indication, when all suction to the miniature power chamber 32 is cut off. Now when the pedal 2li-is moved backwardly the valve 62 will be drawn similarly until the shoulder 18 engages the shoulder 19, causing forward moveent of the valve 4|, imparting a -pull upon the brake rod 5l through the lever 33 and thus operating the master cylinder for applying the brakes. The clevis 45' and the lever I3 are provided with respective lost motion connections |23l to permit full gas acceleration of the motor, since the travel of the follow-up leverage is not sumcient otherwise.

Actual tests .of the brake mechanism have shown a decided decrease in gasoline consumption since spasmodic acceleration is eliminated. wear on the brake mechanism, brake lining and drums reduced to a minimum, as well as producing an harmonious action throughout the driving of the vehicle. In addition, the vehicle may be held on an up-grade surface by the natural decelerating position of the foot-pedal. In fact, the operators foot may be entirely removed from the pedal without interrupting the full braking action of theV vehicle, which feature lends the structure admirably to combat use, where the operator may become disabled to an extent that he might be unable to apply the brakes.

The construction of valve shown in Figures 10 to 14 is especially well suited for use in connection with the use of hydraulic uid, vacuum and high 'pressure air for power in operating the brakes and in Figure 16 there is illustrated a valve and power unit |30. It will be noted that the mechanism is compactly mounted within a supporting bracket |3|, which in the present instance, consists of a base |32, apertured at suitable points for attaching bolts |33, whereby the unit may be mounted upon the chassis of a ve hicle. The base 32has a pair of right angularly disposed arms |34 and |35, arranged in opposed relation and function for support of the valve and power unit, as will now be described. The arm |34 is disposed toward the front of the chassis and upon the front face thereof a power chamber |36 is mounted, the latter having a diaphragm as in the first form of the device, the latter having an operating rod |31 projected throughy anl aperture in the arm |34 and is pivotally connected to the depending arm |33 of the foot pedal |39. The front end of the power chamber |36 has a hose line |40 operatively connected with the intake manifold |4| of the engine |42, and the other elements for control of suction from the manifold are the same as previously described, the same reference characters are employed to designate the parts.

The valve |43 is identical with the construction shown in Figures 10 to 14 and a detailed description of the valve here is not essential to a full understanding of the operation `of the present power unit. The operating rod |44 is` pivotally connected with the lower end of the arm |33 so as to reciprocate the valve either by the power chamber |33 or the pedal |33 the latter being pivotally mounted in ears |33 on .the base |32. The rear end of the valve |43 has a rod |45, corresponding to the rod 45' of the rs't forms, the terminal end of which is operatively connected to a diaphragm `|43 of a hydraulic pressure chamber |41. 1 The chamber |41 has a rearwardly extending rod |48 slidably mounted in a bearing formed upon the arm |35 of the bracket |32. The pressure chamber is of a conventional diaphragm type, but includes a pyramid-shaped spring |49 for holding the diaphragm |48 in normal position. The provision of such a spring provides an even compression throughout the travel of the rod |45.

From the foregoing description, it will be seen that the unit is very compact and may bereadily installed upon a vehicle chassis without dilcult machine operations or material alterations of the vehicle frame or removal of parts. The present construction also permits its installation upon vehicles in which the master cylinder and power chamber may be remotely located as will now be described. In the present inst-ance, we will assume that the master cylinder |50 and power chamber I5| are located under the trunk compartment of a vehicle or within it, although if the design of the vehicle requires these devices be located under the hood of the vehicle, they may be so placed. In such installations, the suction line |52 of the valve |43 is of a length to be operatively connected to the power chamber |5| as at |53 so as to actuate the rod |54 to effect movement of the lever |55 of the master cylinder for forcing iluid through hose lines |56, |51, |58 and |59 so as to operate respective wheel brake units. In the line |55, a T-ttlng is installed serving for connection of a hose line IGI which is connected to the rear of the pressure chamber 41 as indicated at |82, admitting braking uid under pressure" within the chamber for flexing the diaphragm |46. The valve |43 also includes a hose connection |63 which leads to a vacuum storage tank corresponding to the tank 60 of the ilrst forms.

The operation is the same as in the rst forms of the device, except that the slide of the control valve |43 is effected by fluid pressure within the pressure chamber` |41 rather than through a brake rigging. Obviously, it will be possible to actuate the pressure chamber |41 by means of air pressure rather than by iluid, the only alteration in the structure being in the tension of the spring I 49.

While I have speciiically shown and described my brake system, this is by way of illustration only, and I consider as my own all such variations in construction as fairly fall within the scope of the appended claims.

I claim:

1. In a combined brake and accelerating mechanism for a motor vehicle, the combination of a master cylinder, a power chamber having a brake rod operatively connected to the master cylinder, a control valve having a suction port connected with the *iower chamber and an inlet port operatively connected to the intake manifold of the engine of the motor vehicle, a combined accelerator and brake pedal having operative connection with the control valve, a power chamber having operative connection with the intakev manifold of the engine and including a connection with the combined accelerator and brake pedal, the suction created in said last named power chamber holding the control valve in open position.

2. In a combined brake and accelerator mechanism for a motor vehicle, the combination of a master cylinder. a power chamber having a brake rod operatively connected to the master cylinder, a control valve having a suction l0 port connected with the power chamber and an inlet port, a storage tank having a hose line connected with the inlet port of the control valve, a hose line connected to the storage tank and the intake manifold of the engine and including a check valve operative to create a vacuous condition in the storagetank, a combined accelerator and brake pedal having operative connection with the control valve. a power chamber in advance of the accelerator-brake pedal and having a connection therewith and a suction line connected between the forward end of said power chamber and the intake manifold of the engine of the motor vehicle whereby suction created in the last named power chamber will move said accelerator-brake pedal and control valve into braking position.

3. The structure of claim 2 in which the suction line between the last named power chamber and the intake manifold includes a valve having a plurality of ports of different diameters whereby rate of vacuum in the last named power chamber may be established.

4. In a combined brake and accelerating mechanism for a motor vehicle, the combination of a master cylinder, a power chamber having a brake rod operatively vconnected to the master cylinder, a control valve housing having a suction port and an inlet port, a hose line connecting the suction port and the power chamber at the rear thereof, a vacuum storage tank having a hose line connected with the inlet port of the control valve housing, a valve reciprocable to lcontrol the inlet and suction ports, a hose line connected to the storage tank and the intake manifold of the engine of the motor Vehicle and including a check valve operative to create a vacuous condition in the tank, a combined accelerator and brake pedal having a depending leg, a rod connected between the leg and the reciprocable valve, a power chamber including a diaphragm positioned in advance of the depending leg, a rod connected between the diaphragm of the last named power chamber and the leg, a suction line connected between the forward end of said last named power chamber and the intake manifold of the engine whereby suction created in said last named power chamber will move said accelerator-brake pedal to braking position and said reciprocable valve into operative position for control of vacuum in the first named power chamber to actuate the master cylinder.

5. The structure of claim 4 in which the suction line between the last named power chamber and the intake manifold includes a control valve having a plurality of ports of different diameters whereby the rate of vacuum in the last named power chamber may be established.

6. In a combined brake and accelerating mechanism for a motor vehicle, the combination of a master cylinder, a power chamber having a brake rod operatively connected to the master cylinder, a control valve housing having a suction port and an inlet port, a hose line connecting the suction port and an inlet port, a hose line connecting the suction port and the power chamber at the rear thereof, -a vacuum storage tank having a hose line connected with the inlet port of the control valve housing, a valve reciprocable l to control the inlet and suction ports, a hose line connected to the storage tank and the intake manifold of the engine of the motor vehicle and including a check valve operative to create a vacuous condition in the tank, said valve housaccesar lpower chamber in advance of the depending leg,

a rod connected between the diaphragm of said power chamber and the leg, a suction line connected between the forward end of the last named powerl chamber and the intake manifold of the engine, whereby suction created in the said last named power chamber will move said accelerator and brake pedal to braking position and said reciprcable valve into open operative position for control of iluid pressure in the rst named power chamber to acuate the master cylinder, said suction line including a control valve having ports of varying diameters and a full cut-ofi position, and said valve housing and said reciprocable valve having cooperative stop means to effect forward movement of the housing and associated projection when said last named control valve is in full cut-oi! position to eifect forward movement of the brake rod and operation of the master cylinder.

7. The structure of claim 6, in which the engine of the motor vehicle includes. a carbureting means having a throttle valve, a cylinder, a suction piston disposed within the cylinder and operatively connected to said throttle valve, and a said accelerator-brake pedal in brake-applying position. a second power chamber, a control valve having a suction port operatively connected to said power chamber and an inlet port operatively connected to the intake manifold of the engine, said control valve including a reciprocable valve for controlling suction between the inlet and suction ports and having one end connected to the combined accelerator-brake pedal, a master cylinder, said second named power chamber having a piston operatively connected to said master cylinder for actuating the latter and yieldins pressure means between said last named power v chamber and said control valve whereby to regusuction line connected between said cylinder and y `on the diaphragm being such as to maintain the inlet and suction ports in open relation.

10. The structure of claim 8 in which the rst named power chambenbrake pedal, the control valve and pressure means are mounted within a frame as a unit.

HARLEY C. MACK.

REFERENCES crrEn The following references are of record in the file of this patent:

UNITED` STATES PAI'ENTS Breese Apr. 13, 1943 

